[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [Xen-users] Shared Storage

Hi Guys,

Please forget the "thousands" number. We would have thousands of DomUs, but this would be spread over multiple storage servers, so never mind about that scale.

If I was exporting "One big LUN" per Xen node, it would contain at most 80 DomU LVs (In real world usage, closer to 50). Furthermore, each LUN would be exported from a seperate RAID array. Each storage server would contain x number of RAID arrays, where x equals the number of Xen nodes and the number of exported LUNs.

Of course, if I went with one LUN per DomU, then each storage server would contain 80x LUNs (closer to 50x though).

With these numbers, any idea which is better?


-----Original Message-----
From: Bart Coninckx [mailto:bart.coninckx@xxxxxxxxxx]
Sent: Sun 24/04/2011 19:36
To: Jonathan Tripathy
Cc: Jonathan Dye; Xen List
Subject: Re: [Xen-users] Shared Storage

That is completely dependent on your hardware specs and DomU's properties.
It sounds like a lot though. I seem to remember some time ago you also
stated to want to run at least 100 DomUs on one hypervisor, maybe this
is again pushing it.
With a decent RAID and 10gbit or infiniband you can go a long way
though. You should also consider using SCST instrad of IET as it is faster.


On 04/24/11 20:31, Jonathan Tripathy wrote:
> We're talking houndreds, if not thousands of DomUs here. Will iSCSI on
> Linux scale to these large numbers?
> Thanks
> On 24/04/2011 19:13, Jonathan Dye wrote:
>> Why not create one iscsi lun per vm disk instead of carving them up on
>> the hypervisor? That's more typical, and a more typical state of
>> affairs in linux is your friend. Also, you would have just one lun
>> queue if you exported one big PV, instead of one lun queue per vbd.
>> That becomes a problem at scale.
>> - Jonathan
>> ----- Original Message -----
>> From: "Jonathan Tripathy"<jonnyt@xxxxxxxxxxx>
>> To: "Xen List"<xen-users@xxxxxxxxxxxxxxxxxxx>
>> Sent: Sunday, April 24, 2011 11:25:38 AM
>> Subject: [Xen-users] Shared Storage
>> Hi Everyone,
>> I am consider such a setup where I export an iSCSI target to a Xen node.
>> This Xen node will then use the iSCSI block device as an LVM PV, and
>> create lots of LVs for DomU use.
>> I was wondering if anyone could make me aware of any special
>> consideration I would need to take. I've posted a similar question to
>> the LVM list to ask for further tips more specific to LVM.
>> Am I barking down the wrong path here? I know it would be very easy to
>> just an NFS server and use image files, but this will be for a large
>> scale DomU hosting so this isn't really an option. Additionally, if I
>> wanted to make the LVM VG visible to multiple Xen nodes, is it just a
>> matter of running CLVM on each Xen node? Please keep in mind that only
>> one Xen node will be using an LV at any one time (so no need for GFS, I
>> believe)
>> Any help or tips would be appreciated
>> Thanks
>> _______________________________________________
>> Xen-users mailing list
>> Xen-users@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-users
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users

Xen-users mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.